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Seismic anisotropy at Hydrate Ridge
Author(s) -
Kumar Dhananjay,
Sen Mrinal K.,
Bangs Nathan L.,
Wang Chengshu,
Pecher Ingo
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl023945
Subject(s) - anisotropy , clathrate hydrate , geology , isotropy , ridge , hydrate , seismic anisotropy , seismic velocity , mineralogy , seismology , geophysics , petrology , optics , chemistry , paleontology , physics , organic chemistry , mantle (geology)
P‐wave velocity increases in the presence of gas hydrates and decreases in the presence of free gas in the sediments, making it an excellent means to investigate gas hydrate systems. However, seismic velocity is typically derived from surface seismic data without consideration of seismic anisotropy. The presence of anisotropy in the hydrate bearing sediments adds an additional complexity in data analysis; however anisotropy can help reveal the distribution of hydrates. Here we report on the evidence of seismic anisotropy at Hydrate Ridge along the Cascadia convergent margin. We find that the south summit is anisotropic, while the basin side (east of south summit) is isotropic. Anisotropy is likely caused by the hydrate veins. We interpret the anisotropy parameters in terms of the distribution and fabric of gas hydrates.